Propulsion of aircraft and gas turbines



F. wHnTLE 2,168,726

PROPULSION 0F AIRCRAFT AND GAS TURBINES Filed Feb. 27, 19:57 2sheets-sheet 1 wmv..

wh n Aug. 8, 1939.

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Aug'. 8, 1939. F. wHlTTLE 2,168,726

PROPULSION OF AIRCRAFT AND GAS TURBINES Filed Feb. 27, 1937 2Sheets-Sheet 2 f4 n BOX ANAL FLOW rana/NE AxmL no w compnsssn.

Patented Aug. 8, 1939 PATENT oFFicE raorotsron or Amcmlr'r m vcas mamasFrank wmme, mmpinmn, mund Application February 27, 1937, Serial No.128,167

` In Great Britain March 4, 1936 'I'his invention refers to apparatus,the function of which is to provide a supply of working fluid at apressure above that of the atmosphere for the purpose of propelling anaircraft by uid reaction, such propulsion being commonly known as "jetpropulsion".

A known form of .such an apparatus is one in which a centrifugalcompressor compresses'alr into a combustion chamber wherein it isintended to be heated atconstant pressure by the burning of a suitablefuel, the heated products of com- .bustion then expanding through thenozzles of ther expansion, forms a supply of working uid a turbine, thefunction of which is 'to drive the compressor and any desiredauxiliaries. The uid leaving the turbine, being capable of fur- \for theproduction of power as that cited above.

In a reaction propulsion system for boats or air-craft, a prior proposalis the provision of a compressor followed by a burner and deliveringthrough propulsion nozzle means, the compressor being fed by fluid takenin at a pressure created by movement of the whole vehicle in the uidmedium, and it is mentioned that the internal combustion engine whichdrives the compressor may be fed by part of its output. The termcombustion engine as herein used includes any engine which compressesair, effects combustion in it, and is operated by the expansion-ofthecombustion products, and thus in various ways, such includes areciprocating internal combustion engine or a compressor-burner-turbinecombination in which the turbine drives the compressor.

The purpose of this invention is to provide an pose that the inventionisprimarily applicable.

-According to the invention, there is combined in va fluid-reactionpropulsion system for aircraft an air compressor which in eifect dividesthe output\ from the compressor into a rst stream which is passed outthrough a propulsion nozzle .and a second stream, a combustion enginesupplied by the second stream, and a gas turbine supplied wholly orpartly by the eiiluent gas from said engine and driving the said aircompressor.

In this system the combustion products of the engine preferablycontribute to the thrust by uid reaction, for example joining the mainflow from which they were originally diverted before combustion. Theengine referred to may be a compressor-burnr-gas .turbine combination.The system is embodied, in accordance with'the invention, in a unit foraircraft propulsion, and this in two examples takes the formdiagrammatically illustrated in the drawings. Where a gas turbine isemployed it may be adapted to operate with a plurality ofstages ofcompression of the kind in which the compressor means is in the form ofa bilateral intake centrifugal compressor and may generally follow theform de scribed in relation to my British patent specification No.456,980 and to my United States application Serial No. 78,282, filed May6, 1936, now abandoned. It may be convenient to provide the v. wholedevice in the form of a hollow nacelle with an entry opening to face thedirection of travel v (whereby incidentally a certain head of pressuretermed "Pitot pressure.may be derived) and in such nacelle all those`components apt to lose heat may be completely housed to conserveenergy. The inventionl is further to be understood by reference to thefollowing description. Where the description or claims seem to refer tothe whole or a determined part, of a flow, it is to be understood that aportion thereof may be separated and utilized for such purposes asdriving n auxiliaries, heating, etc.

use it may be important to select the directions of rotationA ofrotatable parts, having regard to their gyrostatic reactions.Considering this apparatus as comprising virtually a port and astarboard intake and vaccompanying reaction iets, only one side will bedescribed, the other, apart from any question of rotational direction,being substantially identical. The initial compressors are of the axialflow single-stage type, whilst the internal combustion engine includes aconintake orifice Il, and discharging into a nacelle `52 `within which,behind` the compressor 5U is drivinggearllpoweredbyashaft connected to adriving turbine within a casing 56A. The main flow created in the firstplace by the compressor IlA and subject to any Pitotpressure at 5I ofwhich advantage can` be taken, passes rearwardly through the nacelle 52to emerge from the noule 52A. The flow from the lcompressor I isdivided, part of it is diverted (and any suitable guiding means such asbailles 56A may help to divert it) into a `lateral trunk it `which iscommon to both starboard and` port nacelles. Within the trunk` II ishoused a two-stage bilateral intake compressor, a fuller description ofwhich can be found in the specification of my application Serial No.`18,282 and my British patent specification No. 456,976. In short, thiscomprises twinrst stage compressors 51 outputting to the `second stagecompressor I8. From the secondary diffuser of the compressor l thesecond stage output is led to a combustion chamber i which is connected`to and discharges into the delivery `chamber' Il of a turbine, themechanical output of which drives the compressor shaft il commento bothI1 and 5l.` In` the combustion chamber ,a suitable fuel-burning meansila, arranged `for example somewhat in the manner of that described inrelation to the above numbered specifications, This unit comprising`compressor' means, combustion means,

and turbines, is a combustion engine. It is here Vnoted that as betweenport and starboard sides of the whole apparatus the working directionsmust of course be appropriate for both port and starboard turbines todrive the shaft Il mutually. The combustion efluent expands through thevanes ofithe gas turbine rotor t2 land by a passage t3, ll, Il isdelivered to the nozzle scroll of the turbine II through which thesegases l expand further rejoining the main flow in the nacelle` i2throimh the exhaust il.

In the alternative illustrated diagrammatically in Figure 2, thepropelling unit comprises a `nacelle or duct Il with'a forwardly facingentry Aianda rearwardly facing exit or propulsion nozzle IIB. Thisnacelle encloses within its entry IIA an axial flow compressor withrotor Il driveniby a shaft 32 from an axial flow tur bine rotor 33. Inpractice there will be stepdown gearing All` between the turbine 33 androtor 3|;` Also4 within the nacelle 3l is a compression ignition enginerepresented at 34;` this` engine drives throughits gear box 34A acentrifugal bilateral intake compressor 35 with its intakes (indicatedby arrows) collecting from 1 the interior of thenacelle 30. The outputof the compressor 35 is led by a duct indicated at 36A which leads suchoutput in the direction of the arrow to the nozzle scroll 31 of theturbine I3. the emuent therefrom escaping `through the aisance duct 3land a rearwardly facing propulsion noszle il with such energy as remainsafter passage through the turbine ll. This unit therefore consista in afirst compressorl with divided output, a second and centrifugalcompressor intaking the diverted flow of air driven by and supplyingpart of its `air output to the compression ignition engine ,the exhaustfrom which rejoins the rest of the air supply from the said secondcompresser to form' the working fluid in the turbine Il. To this end theengine 34 has its air intake 34B in the duct 36A and its exhaust IICreturningtothat duct. If desired, the engine 34 may also have lits ownsupercharger, and of course its own auxiliary apparatus. The wholeoutput of the first compressor is finally employed for reactionpropulsion.

What I claim is:

1. A gaseous jet reaction propelling unit for aircraft, comprising anair duct with an entry opening to face the direction of travel, an axialflow compressor therein, a centrifugal compressor supplied with part ofthe flow therefrom, a fuel burning device in the output of thecentrifugal compressor, a turbine driving the centrifugal compressor andoperated by the flow from `said centrifugal compressor and burningdevice, asecond turbine driving the axial flow compressor and operatedby the exhaust 'gases from the first turbine, an exhaust passage fromthe second turbine into the duct behind the axial flow compressor, andan outlet orifice for the duct facing oppositely to the entry.

2. A unit according to claim 1, in which there are two ducts andassociated axial flow compressors and secondturbines, and a singlecentrifugal compressor `unit 4connected and `cooperating `with bothducts.` A

3. Inaiiuid `reaction propulsion vsystem for aircraft, `a combination ofan air compressor; a propulsion nozzle, means for dividing the outputfrom the compressor into alfirst stream which is passed out through thepropulsion nozzle and a second stream, a combustion engine supplied bythe second stream, and a gas turbine supplied atleast partly by theeilluent gas from said engine and driving said air compressor.

4.A system as set forth in claim 3 in which means are provided wherebythe exhaust gases from the turbine also contribute to the thrust by nuidreaction.

5. A system as set forth in claim 3, in which means are provided wherebythe exhaust gases from the turbine rejoin the remainder of thecompressor output before final expansion.

8. A system as claimed in claim 3 in which said engine includes a gasturbine other than that which drives said compressor, said gas `turbinebeing a constant pressure gas turbine, and a centrifugal compressor forsupplying gas under pressure for said gas turbine and connected theretoand driven thereby.

FRANKWHITILE.

